Damascus steel blades are known for their extreme resilience and swirling two-toned bands. The method by which historical Damascus steel was produced is hotly debated, but high-quality knives made via a similar process are still available for the discerning aficionado. The banded inclusion draped over the finish of this container is also made of iron, but unlike Damascus steel, it would not make a very good sword. Most of the metal has reacted with sulfur in the glass melt to create iron sulfide. The iron sulfide blister was then elongated during the forming process into the blade-like inclusion shown here.